Atletico Madrid missed the chance to go top of La Liga after Deportivo's Lucas Perez cancelled out Tiago's volley in a 1-1 draw at the Riazor.
A tight first half was lifted by Tiago's brilliant strike on the half hour and while Deportivo improved after the break, they had to wait until the closing stages to equalise.
Perez hustled Jose Maria Gimenez into making an error and he beat Jan Oblak in the Atletico goal with a well-taken low finish.
It was Perez's sixth goal of the campaign, matching his tally from the whole of last season.
Diego Simeone's men had won their last three in all competitions and would have jumped above Clasico rivals Barcelona and Real Madrid to the summit of La Liga with a victory.
Although Deportivo have now failed to win in their last four games, and remain winless in eight against Atletico, their bright start to the season, which has seen them lose just twice goes on.
With a long-haul trip to Astana for Tuesday's Champions League action to come, Atletico struggled to find a breakthrough, despite starting on the front foot.
Jackson Martinez saw an early snapshot blocked by Sidnei, but the Colombian and strike partner Antoine Griezmann were soon starved of service as the visitors struggled to click.
But their probing finally paid off just after the half-hour. Martinez made a nuisance of himself in the box and, when Sidnei half-cleared the ball to Tiago, the Portugal midfielder rifled a fine volleyed finish into the bottom corner.
Oblak was then called into his first action of the game, having to control a misplaced backpass on his chest and clear under pressure.
Atletico could have made it two from the next attack. Diego Godin's header hit the post and the ball bounced off Griezmann into German Lux's grateful arms.
Griezmann then hit the side netting with a header in the last minute of the half, with 1-0 flattering the hosts at half-time.
Deportivo were much better after the break and went close just three minutes into the half, Fede Cartabia jinking into a shooting position but getting the finish all wrong.
Laure and Cartabia then combined well but Oblak saved the latter's effort comfortably before again stopping a speculative effort from the Argentine midfielder.
Simeone's side seemed content with a single goal but it was not enough to seal the win.
Perez forced a mistake from Gimenez with just 12 minutes to go and kept his nerve to beat Oblak from close range.
Neither side could force a winning goal in a tense last few minutes although Feycal Fajr almost won it for Deportivo but he smacked the bar with a glorious curling effort from well outside the box on 87 minutes.
Simeone will rue two dropped points with title rivals Barca and Real both in action on Saturday.
